Apparatus for the stringing of tennis rackets



Feb. 26; 1935.

J. H. PROCTOR APPARATUS FOR THE STRINGING OF TENNIS RACKETS Filed June22, 1932 4? ff 200M Patented Feb. 26, 1935 UNITED, STATES PATENT OFFICESThis invention consists in apparatus for stringing tennis rackets.

In the practice of the trade the longitudinal string is first drawnthrough the holes in the racket frame starting from the central stringsand working outwards, the frame is then strutted longitudinally toprevent distortion and the string lengths are then separately tautened'up and tensioned successively; as each length is drawn taut by theworkman it is checked by pushing an awl wedge into the outgoing hole inthe frame so as to jamb it, and it is then twanged, the sonorcus noteemitted being the indicator relied on by the workman for ascertainingthe degree of tension.

After the mains or longitudinal strings are thus tensioned and secured,the cross strings are similarly drawn through the appropriate holes inthe frame, and like the longitudinal strings are then tautenedtensioned,and secured.

Continuous strings for the longitudinal courses and for thetransversecourses are used in my stringing method which followsconventional practice insofar as the insertion and awling of strings isconcerned; each separate string length in the lattice being separatelytensioned. Change in the tension strings due to the stretching of anyparticular string course is checkedby frictional resistance where thestrings are reeved through the holes in the frame.

According to the present invention, the racket frame is cramped up tosymmetrical shape on an open centre fiat oval ring carrier by means ofdemountable screw cramps which bear against the outer periphery of thebow. The racket frame is thus held firmly during thestringing operationand distortion of the frame shape is prevented. Any one of the screwcramps is removable during the stringing operation where it is foundnecessary to obtain access to a frame hole which happens to be solocated that it is obstructed by it; when any cramp is thus removed itis replaced temporarily by a like cramp in a close-by position, therebyto maintain the symmetrical shape of the racket frame as the stringingproceeds. The cramps are also adjustable to suit rackets differing incontour, from one another. For factory operation the ring carrier isdetachably fixed on a turntable to enable the operator to reverse theframe end-for-end or side-for-side as the stringing proceeds, thus torelieve him of the necessity for moving his position, to obviate loss oftime, and generally to facilitate the manipulations.

APPARATUS FOR THE STRINGING OF TENNIS RACKETS' Application June 22,1932, Serial No. 618,746

In Australia July 10, 1931 In the drawing:- i l Fig. 1 is a plan view ofa racket frame cramped on a carrier ring, withits handle cramped on anextension arm on which the ring is supported;

Fig. 2 is a plan View of a turntable fixed on a workbench with a pedalpull line for operating the tensioning tool; 1 I

Fig. 3 is a side elevation showing a ring frame with a racket thereonset up on'the turntable (Fig. 2) and 'a pedal line connected to thetensioning tool; i

Fig. 4 is a perspective view of one of the screw pad cramps and Fig. 5is a fragmentary section explanatory of the mounting of the turntable ona ring bed.

The oval ring carrier frame is fixed to the bench arm 11 byscrews. 12,the arm 11 being clamped or bolted to a fixed table, a bench, or a post.Holes 13 are-drilled down through the 5 Claims.

(Fig. 4). Each cramp is provided with a screw 15 which is tapped throughthe cramp headpiece 16 from which the studs 14 depend; its point bearsagainst the downturned end 17 of the saddle pad 18 which is looselylocated by its downturned tailpiece 19 through which the stem of thecramp screw 15 passes. These cramps are set up on the ring 10 and on thebench arm 11 as seen in Fig. Land their screws are operated to cramp theracket frame 20 to true shape and i 1 to set it symmetrically with theracket handle. The peripheral part of the frame and the interior part ofit are accessible to the workman. Where any one of the cramps happens toobstruct one of the string holes another cramp is set up in a close-byposition and the obstructing cramp is removed whilst the string is beingmanipulated in the hole', access to which it had prevented.

When required to be used on a turntable (Fig. 2) the carrier ring 10 isfixed to ring 22 by means of screws 21. Ring 22 is fitted with lugs 52through which check screws 50 are passed to engage a peripheral groove51 in the turntable ring 1 22 and a ball race is provided to facilitaterotation of ring 22 on turntable 22 To fix the ring 10 in relation tothe base ring 22 one of the screws 50 may be replaced by a wing screw.

An outrigger 24 with the bearer piece 24 forms a convenient turntablebase. It is screwed down (25) to a support 26. is required to be pedaloperated, a lever 27 is fulcrumed at 28 on the outrigger 24, and aflexible line 29 is carried from the bottom end of the lever 27 over apulley 40 to a pedal (not shown). The top end of the lever is providedwith a ring .10 to receive the dowel studs 14 of the cramps When thetensioning tool shackle or other attachment for pulling on the back endof the tensioning tool 30.

As each course of string is tensioned it is checked temporarily at theoutgoing frame hole by means of a wedge-awl and the next course of thestring is then drawn taut and tensioned and similarly checked, and so onfor all the longitudi nal and transverse string courses successivelyuntil the frame is fully strung.

The tensioning tool 30 seen in Fig. 3 is the subject of my copendingapplication Serial No. 717,851, filed March 28th,'1934.'

Instead of the back check against which the butt end of the rackethandle bears, acheck engaging the concave face of the fore end of theracket bow may be provided on the carrier frame 10.

What I claim as my invention and desire to secure by Letters Patent is:

1. Apparatus for stringing tennis rackets, comprising an open centrecarrier frame, an extension arm on said carrier frame for supporting thehandle of a racket the bow of which is set on the carrier frame, a checkfor locating the racket enclwise on said frame and arm, a clamp forholding the handle centrally on the extension arm, a plurality of screwcramps having stems which are adapted to set into holes in the carrierframe, said cramps exercising inward pressure about the racket bow toadjust its set and shape.

2. Apparatus for stringing tennis rackets, comprising an open centrecarrier frame, having holes about its periphery, a fixed sub-frame onwhich said carrier is rotatably mounted, an extension arm on saidcarrier frame for supporting the shaft of a racket the bow of which isset on the carrier frame, a check for locating the racket endwise onsaid frame and arm, and a plurality of screw cramps having socket stemswhich seat into said holes in the carrier frame, said cramps exercisinginward pressure on the racket bow to adjust its set and shape.

3. Apparatus for stringing tennis rackets comprising an open centrecarrier frame having holes about its periphery and having an extensionarm, a circular sub-frame adapted to be mounted on a fixture, a ballrace supporting the carrier frame on the sub-frame, said sub-framehaving a peripheral groove therein, guide fingers on the carrier framemovable in said groove to position the carrier frame rotatably on thesub-frame, a check for positioning the racket endwise on said frame andarm, and a plurality of screw cramps having stems which seat into saidholes in the carrier frame, said cramps exercising inward pressure aboutthe racket bow to adjust its set and shape.

4. Apparatus for stringing tennis rackets, comprising an open centercarrier frame having holes therein, an extension arm on said carrierframe 'for supporting the handle of a racket the bow of which is set onthe carrier frame, a check for positioning the racket endwise on saidframe and arm, a clamp for holding the handle centrally on the extensionarm, a plurality of demountable screw cramps having stems which seatinto said holes in the carrier frame, said cramps exercising-inwardpressure on the racket bow to adjust its set and shape.

5. Apparatus of the kind described for stringing tennis rackets,comprising a carrier frame having holes about its periphery, and aplurality of screw cramps having stems which seat into said holes, saidcramps being adapted to locate a racket on said carrier frame and toexercise inward pressure about the bow of the racket to adjust its setand shape, each of said cramps being demountable and fixable in anotherposition to facilitate access to the stringing holes without releasingthe bow. l

JAMES HUTTON PROCTOR.

